Acute pancreatitis is an inflammatory disease that causes death in approximately one-third of patients who develop severe disease. It is most often caused by gallstones and alcohol abuse. The primary mechanism of alcoholic pancreatitis appears to be indirect, acting with other genetic and environmental factors to cause disease. A critical clinical observation made in the last two years is that cigarette smoking substantially increases the risk of developing pancreatitis. In addition, the effects of smoking, when combined with heavy alcohol consumption, further increase the risk of pancreatitis. Although the harmful effects of combining smoking and alcohol on the exocrine pancreas have been established clinically, the cellular mechanisms underlying these responses are unknown. One of the most potent and best studied toxins in cigarette smoke is NNK (4-[methylnitrosamino]-1-[3-pyridyl]-1-butanone). This nicotine metabolite can bind with high affinity to specific cellular receptors that could mediate pancreatitis responses. The studies outlined in this proposal will investigate a previously unexplored disease mechanism: whether the cigarette toxin, NNK, directly mediates or sensitizes to alcoholic pancreatitis responses through specific receptors on the pancreatic acinar cell. The studies in the current proposal will 1) Define the effects of NNK alone, and with ethanol, on acute pancreatitis responses in isolated acinar cells; 2) Investigate potential NNK receptors and related signaling mechanisms alone and with ethanol in pancreatic acinar cells; 3) Define effects of NNK alone, and with ethanol, in in vivo models of pancreatitis. The preliminary studies described in this proposal support each Aim. Since many believe that chronic alcoholic pancreatitis is the result of multiple subclinical bouts of acute disease, it is possible that the mechanisms identified here would be common to both acute and chronic disease forms. Findings from this proposal could be broadly relevant to pancreatitis and other diseases in which smoking and alcohol might act together to cause pathology and could also lead to therapeutic targets.